Final answer:
Congress has the power to override a presidential veto with a two-thirds vote, withhold funding for executive actions, and impeach the president as part of the U.S. checks and balances system. The Senate also must approve presidential appointments and treaties.
Step-by-step explanation:
The powers of Congress to overrule the president's veto, limit executive actions, and impeach the president are critical mechanisms within the U.S. government's system of checks and balances. When the president vetoes a bill, Congress can override the veto with a two-thirds majority vote in both the House and the Senate. Additionally, Congress can refuse to fund certain executive actions and has the power to impeach the president, which involves the House of Representatives bringing formal charges and the Senate trying the case.
Moreover, the Senate plays a vital role in ensuring that the president's appointments, including judges and ambassadors, and treaties require Senate approval to take effect. This layered structure ensures that no single branch of government, including the executive, accumulates too much power and that all branches are subject to oversight and accountability.